Many small PMDC motors are used in automobiles and portable tools and are subject to harsh conditions. A fuel pump motor may be mounted on the engine block and subject to very severe G forces, sometimes up to 1OOG, while a larger motor may be used in a hammer drill and subjected to severe shock along the motor shaft. Forces of this magnitude can cause the laminated armature stack used in such motors to move relative to the motor shaft, thus affecting the performance of the motor.